Drug dependence constitutes a global public health problem of enormous economic, social, and medical cost to the international community. Developing countries, in particular, are disproportionately affected, due to both the economic incentives associated with the production of illicit drugs, and the less well-established institutional infrastructure (i.e., facilities and personnel) dedicated to the understanding, treatment and prevention of drug dependence disorders. In this application, we propose a collaborative research training program in the genetics of drug dependence, between Faculty of Medicine, Chulalongkorn University in Bangkok, Thailand (the leading medical research center in Thailand) and the Yale University School of Medicine in the U.S. Three major training mechanisms are proposed for Thai trainees, including long-term (2-yr) predoctoral and postdoctoral fellowships, and brief (3-month) mini-fellowships. We also propose one minor (1-month) "field" exchange training rotation for U.S. trainees with an interest in international collaborative genetics research to study in Thailand. The present training program builds on an extensive research program in genetics of drug dependence at Yale University School of Medicine, and on existing collaborations between investigators at Yale and investigators at Chulalongkorn in the study of drug dependence in Thai population isolates. The program will contribute to the capacity of investigators at Chulalongkorn to conduct state-of-the-art research in genetics of substance dependence through a range of training experiences; and also to contribute to the capacity of Yale investigators to conduct research in Thailand with Thai collaborators, through increased interaction with Thai counterparts. Eventually it will allow us to build, as specified in the RFA, "a critical mass of scientists, health professionals and academics with human genetics expertise and a sustainable research environment at the collaborating developing country institution." The training grant is also specifically designed to serve a major public health purpose by enhancing Thailand's capacity to confront an epidemic of drug dependence that is unprecedented in its history.